German Patent 34 04 459 discloses a method and a device for delivering sheet products in an overlapping manner. Non-overlappingly conveyed products are decelerated in an overlapping unit where they are arranged so as to overlap, and from where they are conveyed and delivered onto a conveyor belt in an overlapping manner. Grippers are respectively decelerated and accelerated with respect to a drum rotating together with the grippers. The grippers move in slots provided in the outer wall of the drum. A folded product is gripped at its leading edge by nine gripper bars which are radially arranged and mounted in two respective rocking arms. During deceleration of the gripper bars the contact between the entire underside of the folded product resting on the drum and the outer wall of the drum rotating at constant speed causes a disadvantageous full-area relative motion between the underside of the folded product and the outer wall of the drum, thus leaving undesired abrasive marks and scratches on the folded product.
A further disadvantage of the device disclosed in the German patent is the fact that each of the nine radially arranged rocking arm pairs is driven separately. This results in an upper speed limit. Moreover, the device requires much space in the folder.
Furthermore, the device disclosed in the German patent can only be used in large cylinders in order t be able to accommodate a sufficient number of gripper systems, which requires much space. An additional major disadvantage of the device is the fact that it is not suitable for high frequencies. The guides in which the axial projections of the gear ring move quickly up and down with each rotation are subject to a high degree of stress, and thus to a high degree of wear and tear. Inaccuracies resulting from the increasing play between the axial projections and the limitations of the guides affect the precision of the delivery.